So I'm calling this a documentary instead of a tutorial because I really, really just figured it out as I was going along and I'm not sure anyone will be able to follow this. I had to try it on a gazillion times to get the fit right in the bodice (and I have the pin scratches to prove it) ...but here goes:

before...I just loved the color of this man's oxford shirt (it kind of looks like denim but it's not)

and after:

And the documentary...I cut off the sleeves and then cut the front from the bottom of the arm hole to the neck. I actually ended up cutting a little more off the top edge, angling in from the bottom of the arm hole to the button placket.

Then I cut off the collar:

I cut open the sleeves and sliced a 2" strip off the long edge of each sleeve, taking the seam edge with it. Then I attached the sleeve to the cut shirt front, right sides together:

Then I gathered the tops of the sleeves. One I gathered along the curved edge and the other in a straight line cutting off the curve just to see how they fit each way. I used the curved edge in the end because I'm big busted. It's pretty cool, cuz there's enough fabric there that you can move the gathering line up or down until it's just right for you:

Then I cut off the top of the back:

then I sewed the edge of the strip I'd cut off of the sleeve way back when to the gathers to create straps. Folded them over, stitched, and attached them to the back:

Then I finally got the nerve to cut off the excess sleeve. I tried it on and adjusted the bodice several times until I liked the fit. I lined up the top of the sleeve with the top of the back and adjusted the gathers along that edge, too, leaving the bottom 5" or so ungathered. This is when it would be great to have a friend to do your fitting or a dummy that was just your size. It was a real pain pinning under my arms by myself! I tapered down below the arm hole to blend with the shape of the sides of the shirt:

Then I stitched and trimmed the side seams. Needless to say, the dress was already hemmed and I really liked where the pocket ended up. All I had to do was turn under the top edge all the way around and top stitch it. Then I made my final strap adjustments and attached them in the back.

I know it's going to be nice and comfy-cool when we get back to the 100+ degree months here in No. Cal!Thanks for looking

I love how you have the straps running off the v-neck. Totally gonna steal that idea for a tank, the the refashioning of my first refashioning I did on a button up I had but didn't quite like the look of....hmm.